In a processing plant, a rotary evaporator, also known as a rotovap, is a crucial instrument. Its main application is in the recovery of ethanol following an extraction or winterization procedure. Despite the fact that we’ll be concentrating on how a rotovap works during a straightforward ethanol recovery, realise that it can also be used to recover a variety of other solvents as long as they are compatible with the gasket materials.
Important Information About Rotovap Distillation
You need to have a thorough understanding of the physical transformation taking place inside the rotary evaporator before learning about rotovap setup and operation. Consider how ethanol and extract must first be separated in a combination before rotovap distillation can take place.
Heat is used to separate the mixture while a vacuum is also created. The boiling point of the ethanol is dramatically lowered as a result. The combination forms a thin layer that covers the inside of the evaporation flask as it rotates. This encourages the ethanol to evaporate more quickly. The vacuum pump draws that vapour into the condenser’s passage.
The ethanol vapour returns to a liquid state as it enters the condensation channel and falls into the collection flask. Finally, the ethanol passes into the collection flask while the original extract is still in the evaporation flask. Then, this ethanol can be utilised again for extraction or winterization.
Ingredients In A Rotovap
You should be aware of the parts that make up a rotovap before learning how to use one effectively for evaporation. For specific component pairings, please see our rotovap turnkey setups.
Rotovap
How many litres you need to recover determines the size of the rotovap. The most popular sizes are, thus, 5L, 10L, 20L, and 50L. The evaporating flask’s size is referred to as the size. It is significant to note that during operation, the flask is typically loaded at 20–40% of its maximum capacity.
Chiller
Rotovap chillers are created specifically. Compared to circulators that are refrigerated, they have a substantially higher cooling capability. They often don’t have as wide a temperature range, though. This is due to the fact that evaporation will only require a bigger cooling capacity rather than extremely low temperatures. When the solvent vapour reaches the condenser, it is heated. The greater cooling capability is intended to maintain a constant temperature in your chiller.
Vacuum Cleaner
Your rotovap should be used in conjunction with an oil-free, chemically resistant diaphragm pump for maximum results. These pumps are substantially more contaminant resistant than rotary vane (oil) pumps but have less depth. Use caution when using an oil pump with a rotovap or it will quickly be damaged.
Chilly Trap
To shield your vacuum pump from further pollution, position the cold trap between it and the rotovap. Rotovaps require cold traps because they can capture any vapours that enter the condenser. The system’s coldest location will be the cold trap. Accordingly, any vapours drawn in by it will condense again in the trap, leaving your vacuum pump dry and contaminant-free.